Right, like the article says, you want to match the octane with what your engine is designed for. In the case of Lexus that is the more premium gasoline. As a rule of thumb though higher octane does not decrease performance unless you you go way over the end and do something like start putting 118 octane racing fuel in your suburban.
Its also a "if the safty inspectors say the tap water is safe but they only drink the bottled water, you should do the same" kind of thing. Do what the experts do, not what they say to do.People like nascar have a dependancy on the best performance and they use the highest octane that the rules will allow.